Military vehicles/crafts are subjected to threats, e.g. in a situation of war, constituting targets for attack from land, air and sea. It is therefore desired that the vehicle is as difficult as possible to detect, classify and identify. For this purpose military vehicles are often camouflaged to the background to avoid detection, classification and identification from the bare eye. Further, they are hard to detect in darkness with different types of image intensifiers. A problem is that attacking crafts such as combat vehicles and aircrafts often are equipped with heat seeking means in which advanced thermal camera system systems are used wherein the vehicles/crafts become relatively easy targets. Users of such IR-systems search for a certain type of thermal contour normally not occurring in nature, usually different edge geometries, and/or large evenly heated surfaces.
In order to protect against such systems different types of techniques are at present used in the area of signature adaptation. Signature adaptation techniques comprises constructional actions and are often combined with advanced material techniques in order to provide an apparent projection of low thermal contrast the vehicles/crafts in such IR-systems.
In FR2826188 thermo-luminescent molecules in shifting layers for camouflaging in among others the thermal range of wavelengths. A problem with such a solution is that it is difficult to achieve in practice. Further, this can not occur with automatic adaptation to a background.
U.S. Pat. No. 480,113 discloses a device where the surface of an aeroplane is heated by conducting a current through metal wires such that they thermally fit to the temperature of the background, wherein an evenly heated surface being an average value of the background is achieved, complicating discovery of the aeroplane, which otherwise would constitute a cold contrast for a hostile aeroplane above this. This solution does not consider camouflaging by means of cooling but only by means of heating, and results in an evenly heated thermal structure, which sophisticated IR-systems would be able to identify.